1) The document describes Mugi Yamamoto's diploma project, called "Stack", which is a compact inkjet printer that sits on top of a paper pile and slowly moves downwards, swallowing the pile as it prints. 2) Research involved disassembling existing printers to understand their mechanics and modifying printers to find a model suitable for the project. An HP printer was found to have a powerful paper pulling wheel. 3) Many sketches, 3D models, and prototypes were made to develop the ideal compact shape for the printer. A thermoformed model demonstrated the size and paper ejection mechanism. 4) The final product consists of injection molded plastic pieces and lightweight interior parts. It has

1. Diploma project
Stack

2. Stack
My diploma project is a compact
ink jet printer, which is placed on
top of a paper pile. When printing,
“Stack” slowly moves downwards
and swallows the pile until no paper
is left. The paper disappears under
the printer and exits on top, where it
creates a new pile.
Thanks to this new way of printing
it is possible to remove the paper
tray, the bulkiest element in common
printers. This concept allows a very
light appearance and avoids frequent
reloading.
Find out more about this project:
www.mugiyamamoto.com/stack
Compact printer
2 3

3. Research
Getting to understand printers C 100 M 0 Y 0 K 0
Cyan
As soon as I had the concept, I had to
find out if my idea could be realized.
Therefore I disassembled existing
printers to learn from their interior
and I modified them.
If the printer is too heavy, the weight
disturbs the function of pulling
the paper off the pile. Therefore
the printer must have the smallest
possible weight while the wheels must
have enough power to overcome
the pressure of the loading. This
combination of conditions turned out
to be a big challenge for my work.
4

4. HP Deskjet 3520
I found out that the newest generation
of HP printers had a very powerful
wheel which pulls in the paper.
The printer has a low energy
consumption and is very lightweight
and supports wifi-printing. For these
reasons it was the ideal model to be
modified for my project.
Printer and Scanner
6 7

5. Canon Pixma iP100
This printer is the smallest one
available on the market. To see more
detail please have a look at the picture
on the folllowing double page.
I opened the Pixma iP100 to learn
about the possibilities of minimizing
printer parts. Then I improved the
interior of my printer with these newly
discovered parts.
The smallest cartridges on the market
Mobile printer
8 9

6. Canon Pixma iP100
The interior parts
10

7. Research
Shape development
How the shape evolved
Magenta
C 0 M 100 Y 0 K 0
To develop the final shape needed
many weeks of research by doing
sketches, 3D-renderings and
styrofoam models.
The challenge was, to give this new
product an iconic, but still simple and
intuitive shape.
12

8. Shape development
The evolution of the shape
14 15

9. Shape development
The evolution of the shape
16 17

10. How should the paper exit?
The printed paper sheets are
distributed with a certain speed. This
makes it possible to keep the exit
very minimal. In spite of the reduced
design, the paper tray is still able to
hold up to 50 printed pages.
Throwing mechanism
18 19

11. 144.7
105.2
50
A-A (1 : 2) spring
The path of paper sheets
396
280
A A
Units in mm
Mugi Yamamoto June 2013 Page 1/1
Stack 1:5
Scale
moving wheel
cartridges
The moving wheel
The moving wheel underneath the
printer is made of rubber to have
the ideal paper friction coefficient.
Because of the spring, the wheel part
is always at the perfect height and
pressure. If the printer is on the paper
pile, it needs bigger force to pull the
paper, the spring is compressed and
is executing maximum force. When
there are only a few papers left, the
wheel is lowered, the spring extended
and the force minimized.
This flexibility means that the wheel
always works, even if there is only one
sheet of paper left.
Handling different heights of paper stacks
20

12. Model making
Giving a shape
Yellow
C 0 M 0 Y 100 K 0
The shape model is made by
thermoformed polyethylene and has
a interior made of MDF and electronic
components. It demonstrates the
size and shape of the printer and the
ejection of the paper.
22

13. 24 2525

14. The interior
Mechanism to throw out paper
26

15. Final product
Outside shell and inside parts
Key
C 0 M 0 Y 0 K 100
28

16. Final product
Specifications
The final shape consists of two
injection molded pieces made of
high-density polyethylene. This makes
it cheap, stable and gives it a good
resistance to chemicals.
The upper part is colored in light grey,
which makes paper sheets lying on
top more visible, while the base part is
black to give the product contrast and
character.
The wires which guide the falling
papers can be folded inwards to
minimize the volume of the printer for
shipping and storage.
The printer has a built in lithium-
polymer battery which allows it to
be run without cable. To run it line
powered, there is a electric cable,
which is also used for charging.
The interior parts are composed of
lightweight aluminium and plastic in
order to keep the weight of the printer
at a minimum.
30 31

17. Not in use Ready Printing Job done
32

18. 34

19. 36

20. Ink cartridges
Lithium polymer accumulator
Main en-
Buttons
Rubber string
Ink pump
Ink sponge
Cartridge engine
Motherboard
Speed controller
Inside view
Internal components
38

21. 40

22. 42

23. ECAL 2013
Mugi Yamamoto
www.mugiyamamoto.com